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目的研究不同质量浓度铅(Pb)胁迫对冬凌草Rabdosia rubescens不同器官抗氧化酶活性和生长的影响,为Pb污染下的冬凌草生长调控提供依据。方法 Pb质量浓度(0、135、270、540 mg/L)、胁迫时间(50 d)分株水培试验,以超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、生长速率、生物量和Pb质量分数为指标,用分光光度计测定抗氧化酶活性、等离子发射光谱仪测定植株Pb质量分数。结果不同质量浓度Pb胁迫下,冬凌草叶片和根系中的SOD活性均表现为先升后降,但叶片中的SOD活性各组之间无显著性差异;叶片中的POD活性在135、270 mg/L Pb胁迫下与对照之间无显著差异,但在540 mg/L下则显著提高,而根系的POD活性在各质量浓度Pb胁迫下均显著低于对照,具体表现为先下降后又逐渐回升;叶片CAT活性随Pb质量浓度的增加而显著提高,而根系的CAT活性均随Pb质量浓度的增加而递减。中、低质量浓度Pb胁迫对冬凌草的生长无显著影响,高质量浓度(540 mg/L)Pb处理与对照组相比,生物量和相对生长速率分别降低33.33%和46.59%。结论 Pb胁迫对冬凌草叶部和根部的抗氧化酶系统活性刺激反应有明显差异;经拟合模型预测分析,比对照相对生长速率降低10%的Pb临界质量浓度为301.99 mg/L(P<0.01)。冬凌草对Pb胁迫表现为较强的抗逆性。
Objective To study the effects of different Pb (superscript 2 +) concentrations on antioxidant enzyme activity and growth of different organs of Rubescens rubescens (Rubulaceae), and to provide basis for the regulation of Rubia cordyceps growth under Pb pollution. Methods Pb (0, 135, 270 and 540 mg / L) and water stress (50 d) were used to study the effects of different concentrations of Pb, Enzyme (CAT), growth rate, biomass and Pb mass fraction were used as indexes. The antioxidant enzyme activity was measured by spectrophotometer and the Pb concentration by mass spectrometry. Results Under different Pb concentrations, the activities of SOD in leaves and roots of Rubescens indica first increased and then decreased, but there was no significant difference in the SOD activity between the two groups. The activity of POD in leaves was 135, 270 Under the treatment of mg / L Pb, there was no significant difference between the control and the control, but it was significantly increased at 540 mg / L, while the activity of POD in roots was significantly lower than that of the control under the Pb stress. Gradually increased. The activity of CAT in leaves increased significantly with the increase of Pb concentration, while the CAT activity in roots decreased with the increase of Pb concentration. The medium and low concentrations of Pb had no significant effect on the growth of A. rubescens. Compared with the control, Pb and Zn treatments at the concentration of 540 mg / L were reduced by 33.33% and 46.59%, respectively. Conclusion Pb stress has obvious differences in antioxidant enzyme activity in the leaves and roots of Leucoonguillara rubra. The predicted critical mass concentration of Pb reduced by 10% compared with the control was 301.99 mg / L (P <0.01). Rubescens showed stronger stress resistance to Pb stress.